Methods providing dual connectivity communication and related network nodes and wireless terminals

ABSTRACT

A network node may be operated to support dual connectivity communication with a wireless terminal as a main network node in cooperation with a secondary network node. Dual connectivity communication with the wireless terminal may be provided in cooperation with the secondary network node. Responsive to deciding to suspend the dual connectivity communication with the wireless terminal, a connection release message may be transmitted to the wireless terminal, a suspension indication message may be transmitted to the secondary network node, and the dual connectivity communication with the wireless terminal may be suspended. While the dual connectivity communication is suspended, a page may be transmitted to the wireless terminal indicating arrival of downlink data for the wireless terminal and then a measurement report may be received from the wireless terminal providing radio link measurement information for radio links with the main network node and/or the secondary network node.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/066,095 filed on Jun. 26, 2018, which was a 35 U.S.C. § 371 nationalstage application of PCT International Application No. PCT/SE2018/050279filed on Mar. 20, 2018, which in turns claims domestic priority to U.S.Provisional Patent Application No. 62/476,627 filed on Mar. 24, 2017,the disclosures and content of which are incorporated by referenceherein in their entirety.

TECHNICAL FIELD

The present disclosure relates to the field of communications, and moreparticularly to methods providing wireless communications and relatednetwork nodes and wireless terminals.

BACKGROUND

For the LTE-NR tight interworking case, it has been agreed to supportfour bearer types, namely: MCG bearer, MCG split bearer, SCG bearer andSCG split bearer. This is illustrated in FIG. 1.

FIG. 1 illustrates supported bearer types for LTE-NR tight interworking.In 3GPP, work is ongoing, both in LTE and NR, toward supporting lightlyconnected UE (inactive mode), which can be considered as an intermediatestate between IDLE and CONNECTED modes, where the UE AS context is keptboth at the UE and RAN, where the UE can still be seen as if it is inconnected mode from the CN point of view and in IDLE mode from the RANpoint of view. The advantage of operating in this mode is reducedsignaling towards the CN and faster transition to CONNECTED mode ascompared to IDLE-CONNECTED mode transitions, while maintaining the UEpower saving advantages of IDLE mode.

As used herein, the terms “inactive”, “suspended”, and “lightlyconnected” are used interchangeably throughout this document. It isstill FFS (For Further Study) whether a UE's inactive <-> connected modetransitions are hidden completely from the CN (Core Network), from bothCP (Control Plane) and UP (User Plane) perspectives. The discussion inthis disclosure relates primarily to the RAN aspects and thus applicableto both cases (i.e. CN is aware of the inactive/connected statetransitions or the state transitions are transparent to the CN).

Handling suspend/resume operations in Dual Connectivity DC scenarios maybe complicated, however, because there are two RAN nodes involved (i.e.,a main node MN and a secondary node SN) and several radio bearer typesthat terminate at the MN and/or SN. Supporting suspend/resume operationsfor DC in the context of LTE-NR tight interworking may be furthercomplicated because the MN and SN belong to different RATs.

SUMMARY

According to some embodiment of inventive concepts, a method may beprovided to operate a network node supporting dual connectivitycommunication with a wireless terminal as a main network node incooperation with a secondary network node. The method can includeproviding dual connectivity communication with the wireless terminal incooperation with the secondary network node. The method can furtherinclude, responsive to deciding to suspend the dual connectivitycommunication with the wireless terminal, transmitting a connectionrelease message to the wireless terminal. The method can furtherinclude, responsive to deciding to suspend the dual connectivitycommunication with the wireless terminal, transmitting a suspensionindication message to the secondary network node. The method can furtherinclude, responsive to deciding to suspend the dual connectivitycommunication with the wireless terminal, suspending the dualconnectivity communication with the wireless terminal. The method canfurther include, while the dual connectivity communication is suspended,transmitting a page to the wireless terminal indicating arrival ofdownlink data for the wireless terminal. The method can further include,after transmitting the page during suspension of the dual connectivitycommunication, receiving a measurement report from the wireless terminalproviding radio link measurement information for radio links with themain network node and/or the secondary network node.

According to some other embodiments of inventive concepts, a method maybe provided to operate a network node supporting dual connectivity witha wireless terminal as a secondary network node in cooperation with amain network node. The method can include providing dual connectivitycommunication with the wireless terminal in cooperation with the mainnetwork node. The method can further include receiving a suspensionindication message. The method can further include, responsive toreceiving the suspension indication message from the main network node,suspending the dual connectivity communication with the wirelessterminal. The method can further include, while the dual connectivitycommunication is suspended receiving a measurement report from thewireless terminal via the main network node, the measurement reportproviding radio link information for radio links with the main networknode and/or the secondary network node.

According to still other embodiments of inventive concepts, a method maybe provided to operate a wireless terminal supporting dual connectivitywith a main network node and a secondary network node. The method caninclude providing dual connectivity communication with the main networknode and the secondary network node. The method can further includereceiving a connection release message from the main network node. Themethod can further include, responsive to receiving the connectionrelease message, suspending the dual connectivity communication with themain network node and the secondary network node. The method can furtherinclude, performing a radio link measurement with respect to the mainnetwork node and/or the secondary network node while the dualconnectivity communication with the main and secondary network nodes issuspended. The method can further include, while the dual connectivitycommunication is suspended, communicating with the main network node.The method can further include, after communicating with the mainnetwork node, transmitting a measurement report to the main networknode, the measurement report including information based on the radiolink measurement performed during suspension of the dual connectivitycommunication.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the disclosure and are incorporated in a constitute apart of this application, illustrate certain non-limiting embodiments ofinventive concepts. In the drawings:

FIG. 1 is a block diagram illustrating supported bearer types for LTE-NRtight interworking;

FIGS. 2A, 2B, and 2C provide a message diagram illustrating networkoperations according to some embodiments of inventive concepts;

FIG. 3 is a block diagram illustrating elements of a wireless terminalUE according to some embodiments of inventive concepts;

FIG. 4 is a block diagram illustrating elements of a network nodeaccording to some embodiments of inventive concepts;

FIGS. 5, 7, 8, and 9 are flow charts illustrating operations of a mainnetwork node according to some embodiments of inventive concepts;

FIGS. 6 and 12 are flow charts illustrating operations of a of asecondary network node according to some embodiments of inventiveconcepts; and

FIGS. 10 and 11 are flow charts illustrating operations of a wirelessterminal according to some embodiments of inventive concepts.

DETAILED DESCRIPTION OF EMBODIMENTS

Inventive concepts will now be described more fully hereinafter withreference to the accompanying drawings, in which examples of embodimentsof inventive concepts are shown. Inventive concepts may, however, beembodied in many different forms and should not be construed as limitedto the embodiments set forth herein. Rather, these embodiments areprovided so that this disclosure will be thorough and complete, and willfully convey the scope of present inventive concepts to those skilled inthe art. It should also be noted that these embodiments are not mutuallyexclusive. Components from one embodiment may be tacitly assumed to bepresent/used in another embodiment.

FIG. 3 is a block diagram illustrating a wireless terminal UE (alsoreferred to as a mobile terminal, user equipment, user equipment node,etc.) according to some embodiments disclosed herein. As shown, wirelessterminal UE 300 may include processor 303 coupled with transceiver 301,and memory 307. Transceiver 301 may include one or more of a cellularradio access network (RAN) interface (also referred to as a RANtransceiver) and/or other wireless network communication interface.Wireless terminal can thus provide wireless communication over one ormore radio links with one or more radio access network nodes (alsoreferred to as base stations, eNodeBs, eNBs, etc.). Processor 303 (alsoreferred to as a processor circuit or processing circuitry) may includeone or more data processing circuits, such as a general purpose and/orspecial purpose processor (e.g., microprocessor and/or digital signalprocessor). Processor 303 may be configured to execute computer programinstructions from functional modules in memory 307 (also referred to asa memory circuit or memory circuitry), described below as a computerreadable medium, to perform some or all of the operations and methodsthat are described herein for one or more of the embodiments. Moreover,processor 303 may be defined to include memory so that separate memory307 may not be required. Wireless terminal 300, processor 303, andtransceiver 301 may thus perform operations, for example, discussedbelow with respect to the message diagram of FIGS. 2A, 2B, and 2C andwith respect to Example Embodiments.

FIG. 4 is a block diagram illustrating a network node 400 according tosome embodiments disclosed herein. As shown, network node 400 mayinclude processor 403 coupled with network interface 405, transceiver407, and memory 409. Transceiver 407 may include a cellular radio accessnetwork (RAN) interface (also referred to as a RAN transceiver) and/orother wireless network communication interface. Network node 400 canthus provide wireless communication over one or more radio links withone or wireless terminals. Network interface 405 may providecommunication with other network nodes/devices such as a plurality ofnetwork nodes, for example to support dual connectivity for a wirelessterminal. Processor 403 (also referred to as a processor circuit orprocessing circuitry) may include one or more data processing circuits,such as a general purpose and/or special purpose processor (e.g.,microprocessor and/or digital signal processor). Processor 403 may beconfigured to execute computer program instructions from functionalmodules in memory 409 (also referred to as a memory circuit or memorycircuitry), described below as a computer readable medium, to performsome or all of the operations and methods that are described herein forone or more of the embodiments. Moreover, processor 403 may be definedto include memory so that separate memory 409 may not be required. Thestructure of FIG. 4 may be applied to a main network node or to asecondary network node in the context of dual connectivity. Network node400, processor 403, network interface 405, and transceiver 407 may thusperform operations, for example, discussed below with respect to MNand/or SN from the message diagram of FIGS. 2A, 2B, and 2C and withrespect to related Example Embodiments.

In LTE, when a decision is made by the network to move the UE toinactive state, the eNB sends the UE an RRCConnectionRelease messagewith the release cause of rrc-suspend and it is also provided with aresumeIdentity. The UE stores the resumeIdentity and UE AS context(including the current RRC configuration, the current security context,the PDCP state including ROHC state, C-RNTI used in the source PCell,the cellIdentity and the physical cell identity of the source PCell);re-establishes all RLC entities (both for SRBs and DRBs); and suspendsall DRBs and SRBs expect SRBO.

When the UE later on wants to resume the connection (in response to anUL data to be sent or a paging request for DL data), it sends anRRCConnectionResumeRequest message with the saved resumeIdentity. TheeNB responds with an RRCConnectionResume message, and both the UE andeNB restore the saved UE context, and data transmission/receptionfrom/to the UE can be resumed. Note that the resume operation can beperformed in an eNB other than the eNB that was serving the UE when theUE was suspended. In that case, the new eNB can perform a context fetch,e.g., by using the Retrieve UE Context procedure from the old eNB (asthe resumeIdentity includes information about the old eNB/cell).

Handling suspend/resume operations in Dual Connectivity (DC) scenariosis complicated because there are two RAN nodes involved (i.e. MN (mainnode) and SN (secondary node)) and several radio bearer types thatterminate at MN or SN. Currently, the specifications do not explicitlyhandle the DC case, and as such it is up to RAN implementation. Somepossible examples are:

-   -   Before the UE is suspended, all bearers except MCG bearers are        released; or    -   When the UE is asked to resume, a new bearer configuration can        be provided in the RRCConnectionResume message (via the optional        radioResourceConfigDedicated IE available), which could either        release the non-MCG bearers or modify them to become MCG        bearers)        Supporting suspend/resume operations in the context of LTE-NR        tight interworking becomes even more complicated because the MN        and SN now belong to different RATs. We now also have support        for a new bearer type (SCG-Split bearer) that is terminated at        the SN.

A complete support of RRC suspend/resume in the LTE-NR tightinterworking case demands the restoration of all the UE's DRBs (i.e.MCG, MCG-Split, SCG, SCG-Split) on resume. However, this could only beachieved if the radio conditions between the UE and the MN/SN have notchanged (e.g. UE has not moved) and the conditions in both MN and SNhave not changed considerably during the time the UE was in inactivemode (e.g. there are available resources at both the MN and SN tosupport all the bearers as when the UE was suspended). Unless the UE hasbeen in inactive mode only for a very short time, these assumptionsdon't hold. For example:

-   -   The UE has moved and the radio conditions with the old SN are        not good anymore        -   UE is now near the cell edge of the SN, or        -   UE is outside the coverage area of the SN    -   There is another SN with a better radio conditions to the UE        than the old SN    -   UE not in the coverage area of any SN    -   UE has moved to the coverage area of another MN, where the old        SN has no Xn connection with        Thus, it may be either impossible or very inefficient to resume        all the bearers when the UE operating in DC. As mentioned above,        one way of dealing with this is by releasing all the non-MCG        bearers when the UE is suspended or resumed. However, doing so        could also end up being inefficient because soon after it could        become apparent (e.g. when subsequent measurement reports are        received) that the UE can be put into LTE-NR tight interworking        mode with the same MN and SN.

According to some embodiments disclosed herein, the above issues may beaddressed and/or mechanisms may be provided to handle suspend/resumeoperations efficiently.

According to some embodiments, mechanisms may be provided to efficientlysuspend and resume a UE operating in LTE-NR tight interworking mode.

With the mechanisms described herein, it will be possible to suspend andresume all the relevant bearers UE operating in LTE-NR tightinterworking to the same MN and SN, if the network and radio conditionsallow it. And when this is not possible, the LTE-NR tight interworkingcan be resumed with any of the combinations of old MN—new SN, new MN—oldSN or new MN—new SN. It is also possible to revert the UE into non-DCmode, if the network and radio conditions don't favor dual connectivity.

-   -   Other advantages may include: reduced signaling and latency        because we don't have to tear down the non-MCG bearers and set        them up again after a while    -   The other way around: we don't try to blindly keep the non-MCG        bearers running and risk loss of data/delay . . . .    -   We can keep data flowing between the SN and UE temporarily (via        the split SCG) even when we don't have radio connection up with        the SN, in the time between partial resumption and full        resumption.

FIGS. 2A, 2B, and 2C illustrates operations according to someembodiments of inventive concepts, and operations of FIGS. 2A, 2B, and2C (identified with operation numbers in brackets which correspond tothe following operations) are discussed in greater detail below.

Disclaimer: In the following discussion, the case of LTE-NR interworkingis discussed where the MN is an LTE node and the SN is an NR node as anexample. However, all the embodiments are applicable to the case wherethe NR node is the master and the LTE is the SN. The embodiments aregenerally applicable to any two nodes operating under the same ordifferent RAT (e.g., LTE-LTE DC, NR-NR DC, LTE-NR DC, X-Y DC, where Xand Y are any two cellular RATs that support DC operation between them).

Operation 1: when the MN decides to suspend the UE, it notifies the SNabout it. When the SN receives such a message:

-   -   it saves the UE AS context from its point of view (i.e.        including the current SN RRC configuration, the current security        context over the SCGs, the SN PDCP state including ROHC state,        C-RNTI used in the PSCell, the SN cellIdentity and the physical        cell identity of the source PSCell);    -   it associates this context with the resumeIdentity provided        along with the indication from the MN, or assigns it a local        identity    -   suspends all SCG and SCG-split bearers.

Operation 2: when the MN decides to suspend the UE, it notifies the UEwith an RRCConnectionRelease command with the rrc-suspend flag on, Whenthe UE receives such a message

-   -   it saves its AS context (i.e. including the RRC configurations        from both the MN and SN, the current security context over the        MCGs and SCGs, the SN PDCP state including ROHC state for all        the bearers, C-RNTIs used in the PCell and PSCell, the MN and SN        cellIdentity and the physical cell identities of the source        PCell and PSCell);    -   suspends all bearers.

Operation 3: when the MN decides to suspend the UE, along with thesuspended message, it can configure the UE to keep performingmeasurements on either or both of the RATs of the MN and SN, while beingin inactive mode. In order not to drain the UE battery, this measurementconfiguration can include:

-   -   indications that the measurement is to be performed at a        periodicity longer than normal operations; and/or    -   the measurement filtering can be done over a shorter interval

Operation 4: A variant of Operation 3, where the UE that is operating inLTE-NR interworking is suspended, it assumes that it has to performmeasurements in the RATs of the either or both of the RATs of the MNand/or SN, after it has gone to inactive state. The parameters thatdetermine these measurements such as the periodicity and filteringdurations can be given to the UE via RRC signaling any time while the UEwas in CONNECTED mode, or can be hardcoded in the UE (e.g. SIM card)

Operation 5: According to Operations 3 and 4, the UE performsmeasurements of the MN and/or SN RATs using the provided/availablemeasurement configurations

Operation 6: When the UE tries to resume later on due to an arrival ofUL data, or a DL data has triggered RAN level paging and it isresponding to that, it can also indicate an indication that ameasurement is available. This can be via an information that can beincluded in the RRCConnectionResumeRequest message or by sending anormal scheduling request on PUCCH.

Operation 7: When the MN receives the resume request from the UE, withan indication it has a measurement report pending (or it receives aseparate scheduling request), it allocates the required resources to theUE in the DL and indicates this to the UE (via normal PDCCH grant info).

Operation 8: As an alternative to Operations 3 to 7, the UE is notconfigured to perform measurements when it is in inactive mode butrather only after the RRCConnectionResume command is received from theMN. This can be understood implicitly by the UE (i.e. if it is aninactive mode UE that was in LTE-NR tight interworking mode beforemoving to inactive mode, it will start measurement when receiving theresume command) or it can be explicit (configuration sent along with theresume command)

Operation 9: As an alternative to Operation 8, the UE is not configuredto perform measurements when it is in inactive mode but starts to do soafter:

-   -   receiving a paging indicating DL data        -   before sending an RRCConnectionResumeRequest message        -   after sending an RRCConnectionResumeRequest message    -   upon arrival of a UL data        -   before sending an RRCConnectionResumeRequest message        -   after sending an RRCConnectionResumeRequest message

Operation 10: The MN, on receiving the RRCConnectionResumeRequest fromthe UE, and before sending RRCConnectionResume command to the UE, sendsan indication to the SN (along with the resumeIdentity) to inform the SNthat the UE is being activated.

Operation 11: Upon the reception of the activation information from theMN, the SN finds the corresponding UE AS context based on theresumeIdentity and performs admission control (to check if it has enoughresources to admit the UE). The SN can respond to the MN the result ofthe admission control. This can be a simple flag/bit indicating successor failure, or it could be a detailed message indicating which of theUE's bearers (i.e. SCG bearers and SCG split bearers) could be admitted.

Operation 12: The SN, if it performs the admission control as ofOperation 11 and if that was a success (i.e. at least one SCG relatedbearer was admitted), or if it performs no admission control, willresume any (admitted, if that applies) SCG-split bearers and configuresthe corresponding protocol entities so that all the scheduling on the DLon these bearers will be made only on the MN leg of the split bearer.The SCG bearers and the SN leg of the MCG-split bearers will remainsuspended.

Operation 13: The MN prepares an RRCConnectionResume message taking intoaccount the admission control information received as per Operation 11.For example, if the received indication was a success, theradioResourceConfigDedicated IE included in the RRCConnectionResumemessage can include all the stored bearers in the UE context (i.e. MCG,MCG-Split, SCG, SCG-split). As another example, if the receivedindication was a failure, the radioResourceConfigDedicated can indicatethe SCG, SCG-split to be released and the MCG-split bearer to beconverted to an MCG bearer. Another example is if the receivedindication contained the detailed admission control result of every SCG,SCG-split and MCG-split bearer, those bearers that were not admitted canbe included in the bearers to be released list.

Operation 14: The MN can also perform admission control on the concernedbearers (i.e. MCG, MCG-split and SCG-split), and the RRCConnectionResumemessage can be prepared based on that on top of (or instead of) that ofOperation 12, in a way similar to that of Operation 12, this timeimpacting the MCG/MCG-Split and SCG-Split bearers. If none of thebearers can be admitted in the SN (as per Operation 12), and the MN alsocan not admit the MCG bearers, an RRCConnectionResumeReject message canbe prepared instead. Operation 15: The RRCConnectionResume message mayoptionally indicate a “partial” or “full” resume flag.

Operation 16: The prepared RRCConnectionResume orRRCConnectionResumeReject message, as per Operations 13 to 15, is sentto the UE.

Operation 17: If the result of Operation 12 to 14 was the preparation ofan RRCConnectionResumeReject message, the MN may initiate a HO procedureto another eNB.

Operation 18: The UE, upon the reception of an RRCConnectionResumemessage, applies the configuration included in theradioResourceConfigDedicated. If no such IE is included, the UE canassume the saved UE AS context still apply. The UE will resume all therelevant MCG, MCG-Split and SCG-Split bearers (i.e. based on the savedUE AS context and/or the received radioResourceConfigDedicated). If the“partial” resume flag was included, the UE will not resume the SCGbearers. The partial resume flag may not be included and the UE mayimplicitly deduce it is a partial resume as it is getting theRRCConnectionResume message before sending a measurement report. For anyMCG-Split or SCG-Split bearers that are resumed, the UE will beconfigured to schedule only on the MN leg in the UL direction. The SCGbearers remain suspended.

Operation 19: The UE, upon getting a scheduling grant, sends ameasurement report to the MN.

Operation 20: The MN, upon getting a measurement report as per Operation19 indicating that the UE has good radio conditions with the SN node andthat node is still the best candidate not for DC, will send anindication to both the SN and the UE that a full resumption of the DCcan be made. The resumeIdentity may be included in the message.

Operation 21: The SN, upon getting the full resumption indication fromthe MN as per Operation 20, resumes the SCG bearers (if any) of the UE(that were admitted as per Operations 11-12, if that applies). It willalso enable scheduling on the SN legs of the SCG-Split bearers.

Operation 22: The UE, upon getting the full resumption indication fromthe MN as per Operation 20, resumes the SCG bearers (if any) of the UE(that were indicated to be admitted as per Operation 18). It will alsoenable scheduling on the SN legs of the MCG-Split and SCG-Split bearers.

Operation 23: The MN, upon getting a measurement report as per Operation19 indicating that the UE the SN node is no more the best candidate forDC (e.g. there may be another SN with a better radio conditions to theUE, or neither the SN node or any other node has good enough conditionsto be added as a secondary node for DC), will initiate SN release and/orchange procedure with the SN and the UE.

Operation 24: In case the SN has to be changed, if the new SN and theold SN share the same PDCP (e.g. centralized PDCP operation in thesecondary network), the SCG and SCG-Split bearer contexts can be resumedin the new SN node, and the impact could be invisible from the UE and MNperspective.

Operation 25: If the resume operation is initiated in a node other thanthe MN where the UE was suspended, the new MN node can fetch the contextfrom the old MN (which it can deduct from the resumeIdentity included inthe resume request). If the old SN has a backhaul link with the MN andit is possible for the two nodes to operate in DC mode, all the previousOperations are applicable with the new node taking the role of the oldMN. If it was not possible to have DC operations between the new MN nodeand the SN, the MN may decide, in responding to the resume request, torelease all the SCG and SCG-split bearers and indicate so to the UE inthe RRCConnectionResume message.

Embodiment 26: In accordance with the above embodiments, if the UE hasbeen configured to do measurement reporting in inactive state, and sendsthe measurement report along with, or immediately after, the resumerequest, the full resumption of DC operations is performed without goingthrough the intermediate partial resumption procedure described above ifthe measurements were indicating favorable conditions for both the MNand SN.

Operation 27: The MN can store the current time when the UE was sent toinactive mode, and start a timer. When the UE requests for resume lateron, the MN can calculate the duration the UE has spent in inactive modeby comparing the current time and the stored time, and based on thatdecide whether to restore the DC related bearers or not. For example, ifthe duration was very short (below a certain configurable durationduration_low), the MN can try to restore the whole DC, while if theduration was very long (above a certain configuration durationduration_high), the MN will not try to restore the DC related bearers orconvert them to MCG bearers. If the duration was intermediate (aboveduration_low and below duration_high), the MN may decide to wait for ameasurement report before trying to restore the whole DC context and inthe mean time proceed with the partial resume as described in some ofthe embodiments above

Operation 28: The UE can be configured with two timer values,duration_low and duration_high, upon or before being sent to inactivemode. The UE may start performing measurements, if configured to domeasurement in the inactive mode, only if it stays in the inactive modefor at least duration_low. If the UE stays too long in inactive mode(longer than duration_high), it stops performing measurements. Onresume, the UE may send the measurements only if it was inactive for aduration between duration_low and duration_high.

Operations of main network node 400 will now be discussed with referenceto the flow chart of FIG. 5. For example, modules may be stored inmemory 409 of FIG. 4, and these modules may provide instructions so thatwhen the instructions of a module are executed by processor 403,processor 403 performs respective operations of the flow chart of FIG.5. Moreover, the network node of FIG. 4 may be either a main networknode or a secondary network node.

Methods of operating a main network node (MN) supporting dualconnectivity, DC, communication with a wireless terminal (UE) incooperation with a secondary network node (SN) will be discussed withrespect to the flow chart of FIG. 5. Network node processor 403 mayprovide dual connectivity (DC) communication with the wireless terminalin cooperation with the secondary network node at block 501, e.g., usinga DC module. At block 503, processor 403 may decide whether to suspenddual connective communication for the wireless terminal.

Responsive to deciding to suspend the dual connectivity communicationwith the wireless terminal, processor 403 may transmit a connectionrelease message to the wireless terminal at block 505, e.g., using aConnection Release Transmission module. Responsive to deciding tosuspend the dual connectivity communication with the wireless terminal,processor 403 may transmit a suspension indication message to thesecondary network node at block 507, e.g., using a suspension indicationtransmission module. Responsive to deciding to suspend the dualconnectivity communication with the wireless terminal, processor 403 maytransmit a measurement configuration message to the wireless terminaldefining radio link measurements to be performed by the wirelessterminal while the dual connectivity communication with the wirelessterminal is suspended at block 509, e.g., using a measurementconfiguration transmission module.

Responsive to deciding to suspend dual connectivity communication withthe wireless terminal, processor may save an access stratum, AS, contextfor the dual connectivity communication with the wireless terminal atblock 511 so that the access stratum context for the dual connectivitycommunication is maintained at the main network node while the dualconnectivity communication with the wireless terminal is suspended,e.g., using an AC context module. Responsive to deciding to suspend thedual connectivity communication with the wireless terminal, processor403 may suspend the dual connectivity communication with the wirelessterminal at block 515, e.g., using a suspension module.

Responsive to deciding to resume dual connectivity communications withthe wireless terminal at block 517, processor 403 may resume dualconnectivity communication with the wireless terminal at block 519,e.g., using a DC communication resumption module. Details of resuming DCcommunication are discussed with respect to FIGS. 2A, 2B, and 2C andEmbodiments 8-11. Operations of block 517 according to differentembodiments are illustrated in FIGS. 7, 8, and 9.

In embodiments of FIG. 7, after suspending the dual connectivitycommunication at block 515 of FIG. 5, processor 403 may receive ameasurement report from the mobile terminal through transceiver 407 atblock 701, with the measurement report providing radio link measurementinformation for radio links with the main network node and/or thesecondary network node. Responsive to receiving the measurement report,processor 403 may transmit a full resume indication through networkinterface 405 to the secondary network node at block 703 to resume thedual connectivity communication with the wireless terminal. Responsiveto receiving the measurement report, processor 403 may transmit a fullresume indication through transceiver 407 to the wireless terminal atblock 705 to resume the dual connectivity communication with thewireless terminal. Responsive to receiving the measurement report,processor 403 may resume dual connectivity communication with thewireless terminal at block 519 of FIG. 5.

In embodiments of FIG. 8, after suspending the dual connectivitycommunication, processor 403 may transmit a partial resume indicationthrough network interface 405 to the secondary network node at block801, with the partial resume indication including the resume identity.After transmitting the partial resume indication, processor 403 mayreceive a measurement report from the mobile terminal throughtransceiver 407 at block 803, with the measurement report providingradio link measurement information for radio links with the main networknode and/or the secondary network node. After receiving the measurementreport, processor 403 may transmit (805) a full resume indicationthrough network interface 405 to the secondary network node at block805, with the full resume indication including the resume identity.Processor 403 may then resume dual connectivity communication with thewireless terminal at block 519 of FIG. 5.

In embodiments of FIG. 9, after suspending the dual connectivitycommunication, processor may transmit (901) a partial resume indicationthrough transceiver 407 to the wireless terminal at block 901, with thepartial resume indication including the resume identity. Aftertransmitting the partial resume indication to the wireless terminal andbefore receiving the measurement report, processor 403 may resume mastercell group bearers, master cell group split bearers, and secondary cellgroup split bearers for the dual connectivity communication with thewireless terminal at block 903 while disabling secondary network legs ofthe master and secondary cell group split bearers. After resuming mastercell group bearers, master cell group split bearers, and secondary cellgroup split bearers, processor 403 may receive a measurement report fromthe mobile terminal through transceiver 407 at block 905, with themeasurement report providing radio link measurement information forradio links with the main network node and/or the secondary networknode. After receiving the measurement report, processor 403 may transmita full resume indication through network interface 405 to the secondarynetwork node at block 907, with the full resume indication including theresume identity. After transmitting the full resume indication to thesecondary network node, processor 403 may enable the secondary networklegs of the master and secondary cell group bearers at block 909.Processor 403 may then resume dual connectivity communication with thewireless terminal at block 519 of FIG. 5.

Various operations of FIGS. 5, 7, 8, and 9 may be optional with respectto some embodiments. Regarding methods of example embodiment 1 (setforth below), for example, operations of blocks 503, 509, 511, 517, 519,701, 703, 705, 801, 803, 805, 901, 903, 905, 907, and 909 may beoptional.

Operations of secondary network node 400 will now be discussed withreference to the flow chart of FIG. 6. For example, modules may bestored in memory 409 of FIG. 4, and these modules may provideinstructions so that when the instructions of a module are executed byprocessor 403, processor 403 performs respective operations of the flowchart of FIG. 5. Moreover, the network node of FIG. 4 may be either amain network node or a secondary network node.

Methods of operating a network node supporting dual connectivity with awireless terminal (UE) as a secondary network node (SN) in cooperationwith a main network node (MN) will be discussed with respect to FIG. 6.At block 601, processor 403 may provide dual connectivity communicationwith the wireless terminal in cooperation with the main network node,e.g., using a DC communication module. Responsive to a suspensionindication at block 603, processor 403 may receive a suspensionindication message, e.g., using a suspension indication receptionmodule.

Responsive to receiving the suspension indication message from the mainnetwork node, processor may save an access stratum, AS, context for thedual connectivity communication with the wireless terminal at block 607so that the access stratum context for the dual connectivitycommunication is maintained at the secondary network node aftersuspending the dual connectivity communication with the wirelessterminal, e.g. using an access stratum saving module. Responsive toreceiving the suspension indication message from the main network node,processor 403 may suspend the dual connectivity communication with thewireless terminal at block 609, for example, using a suspension module.

At block 610, processor may decide to resume DC communication, and atblock 611, processor 403 may resume DC communication with the wirelessterminal, e.g., using a DC communication resumption module. Details ofresuming DC communication are discussed with respect to FIGS. 2A, 2B,and 2C and Embodiments 21-25.

Operations of block 601 according to some embodiments are illustrated inFIG. 12 where the suspension indication message includes a resumeidentity and the access stratum context is associated with the resumeidentity. After suspending the dual connectivity communication andresponsive to a partial resume indication, processor 403 may receive thepartial resume indication from the main network node through networkinterface 405 at block 1203, with the partial resume indicationincluding the resume identity. Responsive to receiving the partialresume indication, processor 403 may resume a secondary cell group splitbearer for the dual connectivity communication at block 1205 based onthe access stratum context while disabling a secondary network node legof the split bearer and while maintaining suspension of a secondary cellgroup bearer for the dual connectivity communication. After resuming thesecondary cell group split bearer and responsive to a full resumeindication at block 1207, processor 403 may receive the full resumeindication including the resume identity through network interface 405at block 1209. Responsive to receiving the full resume indication,processor 403 may resuming the secondary cell group bearer for the dualconnectivity communication at block 1211 based on the access stratumcontext and enabling the secondary network node leg of the split bearerto resume DC communication at block 611.

Various operations of FIGS. 6 and 12 may be optional with respect tosome embodiments. Regarding methods of example embodiment 16 (set forthbelow), for example, operations of blocks 603, 607, 611, 1201, 1203,1205, 1207, 1209, and 1211 may be optional.

Operations of wireless terminal 300 will now be discussed with referenceto the flow charts of FIGS. 10 and 11. For example, modules may bestored in memory 307 of FIG. 3, and these modules may provideinstructions so that when the instructions of a module are executed byprocessor 303, processor 303 performs respective operations of the flowchart of FIG. 10 or 11.

Operations of blocks 1001, 1003, 1005, 1007, 1009, and 1011 are the samefor embodiments of FIGS. 10 and 11, and will be discussed as follows. Atblock 1001, processor 303 may provide dual connectivity communicationwith the main network node and the secondary network node, and at block1003, processor 303 may receive a connection release message from themain network node through transceiver 301. At block 1005, processor 303may receive a measurement configuration message from the main networknode through transceiver 301, with the measurement configuration messagedefining radio link measurements to be performed by the wirelessterminal while the dual connectivity communication with the wirelessterminal is suspended. After receiving the measurement configurationmessage and responsive to receiving the connection release message,processor 303 may suspend the dual connectivity communication with themain network node and the secondary network node at block 1007.Responsive to receiving the connection release message, processor 303may save an access stratum AS context for the dual connectivitycommunication with the main and secondary network nodes at block 1009 sothat the access stratum context for the dual connectivity communicationis maintained at the wireless terminal after suspending the dualconnectivity communication with the main and secondary network nodes. Atblock 1011, processor 303 may perform a radio link measurement withrespect to the main network node and/or the secondary network node whilethe dual connectivity communication with the main and secondary networknodes is suspended, with the radio link measurement being performed inaccordance with the measurement configuration message.

According to embodiments of FIG. 10, processor 303 may transmit a resumerequest through transceiver 301 to the main network node at block 1013while the dual connectivity communication is suspended. Aftertransmitting the resume request, processor 303 may transmit ameasurement report to the main network node at block 1015, with themeasurement report including information based on the radio linkmeasurement performed during suspension of the dual connectivitycommunication. At block 1023, processor 303 may resume the dualconnectivity communication.

According to embodiments of FIG. 11, processor 303 may receive a pagefrom the main network node through transceiver 301 while the dualconnectivity communication is suspended at block 1019, with the pageindicating the arrival of downlink data. After receiving the page,processor may transmit (1021) a measurement report through transceiver301 to the main network node at block 1021, with the measurement reportincluding information based on the radio link measurement performedduring suspension of the dual connectivity communication. At block 1023,processor 303 may resume the dual connectivity communication.

Various operations of FIGS. 10 and 11 may be optional with respect tosome embodiments. Regarding methods of example embodiment 27 (set forthbelow), for example, operations of blocks 1005, 1009, 1013, 1015, 1019,1021, and 1023 may be optional.

Example embodiments according to some embodiments of inventive conceptsare discussed below.

Embodiment 1. A method of operating a network node supporting dualconnectivity, DC, communication with a wireless terminal (UE) as a mainnetwork node (MN) in cooperation with a secondary network node (SN), themethod comprising: providing dual connectivity communication with thewireless terminal in cooperation with the secondary network node;responsive to deciding to suspend the dual connectivity communicationwith the wireless terminal, transmitting a connection release message tothe wireless terminal; responsive to deciding to suspend the dualconnectivity communication with the wireless terminal, transmitting asuspension indication message to the secondary network node; andresponsive to deciding to suspend the dual connectivity communicationwith the wireless terminal, suspending the dual connectivitycommunication with the wireless terminal.

Embodiment 2. The method of Embodiment 1 further comprising: responsiveto deciding to suspend dual connectivity communication with the wirelessterminal, saving an access stratum, AS, context for the dualconnectivity communication with the wireless terminal so that the accessstratum context for the dual connectivity communication is maintained atthe main network node while the dual connectivity communication with thewireless terminal is suspended.

Embodiment 3. The method of Embodiment 2 wherein the access stratumcontext for the dual connectivity communication includes informationregarding master cell group, MCG, bearers for the main network node andsecondary cell group, SCG, bearers for the secondary network node.

Embodiment 4. The method of any of Embodiments 2-3 wherein the accessstratum context for the dual connectivity communication includes radioresource control configurations for the main and secondary networknodes.

Embodiment 5. The method of any of Embodiments 2-4 wherein the accessstratum context for the dual connectivity communication includessecurity contexts for main and secondary cell groups of the main andsecondary network nodes, packet data convergence protocol states for themain and secondary network nodes, robust header compression states forthe main and secondary network nodes, cell radio network temporaryidentifiers for the main and secondary network nodes, and/or identitiesassociated with a PCell and a PSCell.

Embodiment 6. The method of any of Embodiments 1-5 wherein theconnection release message comprises an RRCConnectionRelease commandwith an rrc-suspend flag on.

Embodiment 7. The method of any of Embodiments 1-6 further comprising:responsive to deciding to suspend the dual connectivity communicationwith the wireless terminal, transmitting a measurement configurationmessage to the wireless terminal defining radio link measurements to beperformed by the wireless terminal while the dual connectivitycommunication with the wireless terminal is suspended.

Embodiment 8. The method of any of Embodiments 1-7 further comprising:after suspending the dual connectivity communication, receiving ameasurement report from the mobile terminal providing radio linkmeasurement information for radio links with the main network nodeand/or the secondary network node.

Embodiment 9. The method of Embodiment 8 further comprising: responsiveto receiving the measurement report, transmitting a full resumeindication to the secondary network node to resume the dual connectivitycommunication with the wireless terminal; responsive to receiving themeasurement report, transmitting a full resume indication to thewireless terminal to resume the dual connectivity communication with thewireless terminal; and responsive to receiving the measurement report,resuming dual connectivity communication with the wireless terminal.

Embodiment 10. The method of Embodiment 8 further comprising: aftersuspending the dual connectivity communication and before receiving themeasurement report, transmitting a partial resume indication to thesecondary network node, wherein the partial resume indication includesthe resume identity; after receiving the measurement report,transmitting a full resume indication to the secondary network node,wherein the full resume indication includes the resume identity.

Embodiment 11. The method of Embodiment 8 further comprising: aftersuspending the dual connectivity communication and before receiving themeasurement report, transmitting a partial resume indication to thewireless terminal, wherein the partial resume indication includes theresume identity; after sending the partial resume indication to thewireless terminal and before receiving the measurement report, resumingmaster cell group bearers, master cell group split bearers, andsecondary cell group split bearers for the dual connectivitycommunication with the wireless terminal while disabling secondarynetwork legs of the master and secondary cell group split bearers; afterreceiving the measurement report, transmitting a full resume indicationto the secondary network node, wherein the full resume indicationincludes the resume identity; and after transmitting the full resumeindication to the secondary network node, enabling the secondary networklegs of the master and secondary cell group bearers.

Embodiment 12. The method of any of Embodiments 1-11 wherein the mainnetwork node and the secondary network node are nodes of different radioaccess technologies.

Embodiment 13. The method of Embodiment 12 wherein one of the main andsecondary network nodes is an LTE network node, and the other of themain and second network nodes is an NR network node.

Embodiment 14. A network node supporting dual connectivity communicationwith a wireless terminal as a main network node (MN) in cooperation witha secondary network node, the main network node comprising: atransceiver configured to provide wireless network communication withthe wireless terminal; a network interface configured to provide networkcommunication with the secondary network node; and a processor coupledwith the transceiver and the network interface, wherein the processor isconfigured to provide communication with the wireless terminal throughthe transceiver, wherein the processor is configured to providecommunication with the secondary network node through the networkinterface, and wherein the processor is configured to perform operationsaccording to any of Embodiments 1-13.

Embodiment 15. A network node, wherein the network node is adapted toperform according to any of Embodiments 1-13.

Embodiment 16. A method of operating a network node supporting dualconnectivity with a wireless terminal (UE) as a secondary network node(SN) in cooperation with a main network node (MN), the methodcomprising: providing dual connectivity communication with the wirelessterminal in cooperation with the main network node; receiving asuspension indication message; and responsive to receiving thesuspension indication message from the main network node, suspending thedual connectivity communication with the wireless terminal.

Embodiment 17. The method of Embodiment 16 further comprising:responsive to receiving the suspension indication message from the mainnetwork node, saving an access stratum, AS, context for the dualconnectivity communication with the wireless terminal so that the accessstratum context for the dual connectivity communication is maintained atthe secondary network node after suspending the dual connectivitycommunication with the wireless terminal.

Embodiment 18. The method of Embodiment 17 wherein the access stratumcontext for the dual connectivity communication includes informationregarding secondary cell group, SCG, bearers for the secondary networknode.

Embodiment 19. The method of any of Embodiments 17-18 wherein the accessstratum context for the dual connectivity communication includes atleast one of a radio resource control configuration for the secondarynetwork node, a security context for a secondary cell group of thesecondary network node, a packet data convergence protocol state for thesecondary network node, a robust header compression state for thesecondary network node, a cell radio network temporary identifier forthe secondary network node, and/or an identity associated with a PSCell.

Embodiment 20. The method of any of Embodiments 17-19 wherein thesuspension indication message includes a resume identity, and whereinthe access stratum context is associated with the resume identity.

Embodiment 21. The method of Embodiment 20 further comprising: aftersuspending the dual connectivity communication, receiving a partialresume indication from the main network node, wherein the partial resumeindication includes the resume identity; responsive to receiving thepartial resume indication, resuming a secondary cell group split bearerfor the dual connectivity communication based on the access stratumcontext while disabling a secondary network node leg of the split bearerand while maintaining suspension of a secondary cell group bearer forthe dual connectivity communication.

Embodiment 22. The method of Embodiment 21 further comprising: afterresuming the secondary cell group split bearer, receiving a full resumeindication including the resume identity; and responsive to receivingthe full resume indication, resuming the secondary cell group bearer forthe dual connectivity communication based on the access stratum contextand enabling the secondary network node leg of the split bearer.

Embodiment 23. The method of any of Embodiments 16-22 wherein suspendingthe dual connectivity communication comprises suspending secondary cellgroup bearers and secondary cell group split bearers associated with thedual connectivity communication with the wireless terminal.

Embodiment 24. The method of any of Embodiments 16-23 wherein the mainnetwork node and the secondary network node are nodes of different radioaccess technologies.

Embodiment 25. The method of Embodiment 24 wherein one of the main andsecondary network nodes is an LTE network node, and the other of themain and second network nodes is an NR network node.

Embodiment 26. A network node supporting dual connectivity communicationwith a wireless terminal as a secondary network node (SN) in cooperationwith a main network node, the secondary network node comprising: atransceiver configured to provide wireless network communication withthe wireless terminal; a network interface configured to provide networkcommunication with the main network node; and a processor coupled withthe transceiver and the network interface, wherein the processor isconfigured to provide communication with the wireless terminal throughthe transceiver, wherein the processor is configured to providecommunication with the main network node through the network interface,and wherein the processor is configured to perform operations accordingto any of Embodiments 16-25.

Embodiment 27. A method of operating a wireless terminal supporting dualconnectivity with a main network node and a secondary network node, themethod comprising: providing dual connectivity communication with themain network node and the secondary network node; receiving a connectionrelease message from the main network node; and responsive to receivingthe connection release message, suspending the dual connectivitycommunication with the main network node and the secondary network node.

Embodiment 28. The method of Embodiment 27 further comprising:responsive to receiving the connection release message, saving an accessstratum, AS, context for the dual connectivity communication with themain and secondary network nodes so that the access stratum context forthe dual connectivity communication is maintained at the wirelessterminal after suspending the dual connectivity communication with themain and secondary network nodes.

Embodiment 29. The method of Embodiment 28 wherein the access stratumcontext includes radio resource control configurations for the main andsecondary network nodes.

Embodiment 30. The method of any of Embodiments 28-29 wherein the accessstratum context includes security contexts for bearers of the main andsecondary network nodes, packet data convergence protocol states of themain and secondary network nodes, cell radio network temporaryidentifiers of the main and secondary network nodes, cell identities ofthe main and secondary network nodes, and physical cell identities ofthe main and secondary nodes.

Embodiment 31. The method of any of Embodiments 27-30 wherein suspendingthe dual connectivity communication comprises suspending bearers of themain and secondary network nodes.

Embodiment 32. The method of any of Embodiments 27-31 wherein theconnection release message comprises an RRCConnectionRelease commandwith an rrc-suspend flag on.

Embodiment 33. The method of any of Embodiments 27-32 furthercomprising: performing a radio link measurement with respect to the mainnetwork node and/or the secondary network node while the dualconnectivity communication with the main and secondary network nodes issuspended.

Embodiment 34. The method of Embodiment 33 further comprising: beforesuspending the dual connectivity communication with the main andsecondary network nodes, receiving a measurement configuration messagefrom the main network node defining radio link measurements to beperformed by the wireless terminal while the dual connectivitycommunication with the wireless terminal is suspended, whereinperforming the radio link measurement comprises performing the radiolink measurement in accordance with the measurement configurationmessage.

Embodiment 35. The method of any of Embodiments 33-34, furthercomprising: while the dual connectivity communication is suspended,transmitting a resume request to the main network node; and aftertransmitting the resume request, transmitting a measurement report tothe main network node wherein the measurement report includesinformation based on the radio link measurement performed duringsuspension of the dual connectivity communication.

Embodiment 36. The method of any of Embodiments 33-34 furthercomprising: while the dual connectivity communication is suspended,receiving a page from the main network node indicating arrival ofdownlink data; and after receiving the page, transmitting a measurementreport to the main network node wherein the measurement report includesinformation based on the radio link measurement performed duringsuspension of the dual connectivity communication.

Embodiment 37. The method of any of Embodiments 27-36 wherein the mainnetwork node and the secondary network node are nodes of different radioaccess technologies.

Embodiment 38. The method of Embodiment 37 wherein one of the main andsecondary network nodes is an LTE network node, and the other of themain and second network nodes is an NR network node.

Embodiment 39. A wireless terminal, UE, comprising: a transceiverconfigured to provide dual connectivity wireless network communicationwith main network node and a secondary network node; and a processorcoupled with the transceiver, wherein the processor is configured toprovide wireless network communication through the transceiver, whereinthe processor is configured to perform operations according to any ofEmbodiments 27-38.

Embodiment 40. A wireless terminal, UE, wherein the wireless terminal isadapted to perform according to any of Embodiments 27-38.

Embodiment 41. A network node, wherein the network node is adapted toperform according to any of Embodiments 16-25.

Explanations of abbreviations used herein are provided below.

Abbreviation Explanation

-   -   MeNB: Master eNB    -   SeNB: Secondary eNB    -   TNL: Transport Network Layer    -   UE: User Equipment    -   SCG: Secondary Cell Group    -   MCG: Master Cell Group    -   NR: New Radio    -   AS: Access Stratum    -   CP: Control Plane    -   UP: User Plane    -   CN Core Network    -   FFS: For Further Study    -   ROHC: Robust Header Compression    -   PDCP: Packet Data Convergence Protocol    -   SRB: Signaling Radio Bearer    -   DRB: Data Radio Bearer

Further definitions are discussed below.

In the above-description of various embodiments of present inventiveconcepts, it is to be understood that the terminology used herein is forthe purpose of describing particular embodiments only and is notintended to be limiting of present inventive concepts. Unless otherwisedefined, all terms (including technical and scientific terms) usedherein have the same meaning as commonly understood by one of ordinaryskill in the art to which present inventive concepts belong. It will befurther understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of this specification andthe relevant art and will not be interpreted in an idealized or overlyformal sense unless expressly so defined herein.

When an element is referred to as being “connected”, “coupled”,“responsive”, or variants thereof to another element, it can be directlyconnected, coupled, or responsive to the other element or interveningelements may be present. In contrast, when an element is referred to asbeing “directly connected”, “directly coupled”, “directly responsive”,or variants thereof to another element, there are no interveningelements present. Like numbers refer to like elements throughout.Furthermore, “coupled”, “connected”, “responsive”, or variants thereofas used herein may include wirelessly coupled, connected, or responsive.As used herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. Well-known functions or constructions may not be described indetail for brevity and/or clarity. The term “and/or” includes any andall combinations of one or more of the associated listed items.

It will be understood that although the terms first, second, third, etc.may be used herein to describe various elements/operations, theseelements/operations should not be limited by these terms. These termsare only used to distinguish one element/operation from anotherelement/operation. Thus a first element/operation in some embodimentscould be termed a second element/operation in other embodiments withoutdeparting from the teachings of present inventive concepts. The samereference numerals or the same reference designators denote the same orsimilar elements throughout the specification.

As used herein, the terms “comprise”, “comprising”, “comprises”,“include”, “including”, “includes”, “have”, “has”, “having”, or variantsthereof are open-ended, and include one or more stated features,integers, elements, steps, components or functions but does not precludethe presence or addition of one or more other features, integers,elements, steps, components, functions or groups thereof. Furthermore,as used herein, the common abbreviation “e.g.”, which derives from theLatin phrase “exempli gratia,” may be used to introduce or specify ageneral example or examples of a previously mentioned item, and is notintended to be limiting of such item. The common abbreviation “i.e.”,which derives from the Latin phrase “id est,” may be used to specify aparticular item from a more general recitation.

Example embodiments are described herein with reference to blockdiagrams and/or flowchart illustrations of computer-implemented methods,apparatus (systems and/or devices) and/or computer program products. Itis understood that a block of the block diagrams and/or flowchartillustrations, and combinations of blocks in the block diagrams and/orflowchart illustrations, can be implemented by computer programinstructions that are performed by one or more computer circuits. Thesecomputer program instructions may be provided to a processor circuit ofa general purpose computer circuit, special purpose computer circuit,and/or other programmable data processing circuit to produce a machine,such that the instructions, which execute via the processor of thecomputer and/or other programmable data processing apparatus, transformand control transistors, values stored in memory locations, and otherhardware components within such circuitry to implement thefunctions/acts specified in the block diagrams and/or flowchart block orblocks, and thereby create means (functionality) and/or structure forimplementing the functions/acts specified in the block diagrams and/orflowchart block(s).

These computer program instructions may also be stored in a tangiblecomputer-readable medium that can direct a computer or otherprogrammable data processing apparatus to function in a particularmanner, such that the instructions stored in the computer-readablemedium produce an article of manufacture including instructions whichimplement the functions/acts specified in the block diagrams and/orflowchart block or blocks. Accordingly, embodiments of present inventiveconcepts may be embodied in hardware and/or in software (includingfirmware, resident software, micro-code, etc.) that runs on a processorsuch as a digital signal processor, which may collectively be referredto as “circuitry,” “a module” or variants thereof.

It should also be noted that in some alternate implementations, thefunctions/acts noted in the blocks may occur out of the order noted inthe flowcharts. For example, two blocks shown in succession may in factbe executed substantially concurrently or the blocks may sometimes beexecuted in the reverse order, depending upon the functionality/actsinvolved. Moreover, the functionality of a given block of the flowchartsand/or block diagrams may be separated into multiple blocks and/or thefunctionality of two or more blocks of the flowcharts and/or blockdiagrams may be at least partially integrated. Finally, other blocks maybe added/inserted between the blocks that are illustrated, and/orblocks/operations may be omitted without departing from the scope ofinventive concepts. Moreover, although some of the diagrams includearrows on communication paths to show a primary direction ofcommunication, it is to be understood that communication may occur inthe opposite direction to the depicted arrows.

Many variations and modifications can be made to the embodiments withoutsubstantially departing from the principles of the present inventiveconcepts. All such variations and modifications are intended to beincluded herein within the scope of present inventive concepts.Accordingly, the above disclosed subject matter is to be consideredillustrative, and not restrictive, and the examples of embodiments areintended to cover all such modifications, enhancements, and otherembodiments, which fall within the spirit and scope of present inventiveconcepts. Thus, to the maximum extent allowed by law, the scope ofpresent inventive concepts are to be determined by the broadestpermissible interpretation of the present disclosure including theexamples of embodiments and their equivalents, and shall not berestricted or limited by the foregoing detailed description.

1. A method of operating a network node supporting dual connectivitycommunication with a wireless terminal as a main network node incooperation with a secondary network node, the method comprising:providing dual connectivity communication with the wireless terminal incooperation with the secondary network node; responsive to deciding tosuspend the dual connectivity communication with the wireless terminal,transmitting a connection release message to the wireless terminal;responsive to deciding to suspend the dual connectivity communicationwith the wireless terminal, transmitting a suspension indication messageto the secondary network node; responsive to deciding to suspend thedual connectivity communication with the wireless terminal, suspendingthe dual connectivity communication with the wireless terminal; whilethe dual connectivity communication is suspended, transmitting a page tothe wireless terminal indicating arrival of downlink data for thewireless terminal; and after transmitting the page during suspension ofthe dual connectivity communication, receiving a measurement report fromthe wireless terminal providing radio link measurement information forradio links with the main network node and/or the secondary networknode.
 2. The method of claim 1, further comprising: responsive todeciding to suspend dual connectivity communication with the wirelessterminal, saving an access stratum, AS, context for the dualconnectivity communication with the wireless terminal so that the accessstratum context for the dual connectivity communication is maintained atthe main network node while the dual connectivity communication with thewireless terminal is suspended, wherein the access stratum context forthe dual connectivity communication includes information regarding:master cell group, MCG, bearers for the main network node, secondarycell group, SCG, bearers for the secondary network node, and radioresource control configurations for the main and secondary networknodes.
 3. The method of claim 1, further comprising: responsive todeciding to suspend the dual connectivity communication with thewireless terminal, transmitting a measurement configuration message tothe wireless terminal defining radio link measurements to be performedby the wireless terminal while the dual connectivity communication withthe wireless terminal is suspended.
 4. The method of claim 1, furthercomprising: responsive to receiving the measurement report, transmittinga full resume indication to the secondary network node to resume thedual connectivity communication with the wireless terminal; responsiveto receiving the measurement report, transmitting a full resumeindication to the wireless terminal to resume the dual connectivitycommunication with the wireless terminal; and responsive to receivingthe measurement report, resuming dual connectivity communication withthe wireless terminal.
 5. The method of claim 1, further comprising:after suspending the dual connectivity communication and beforereceiving the measurement report, transmitting a partial resumeindication to the secondary network node, wherein the partial resumeindication includes the resume identity; and after receiving themeasurement report, transmitting a full resume indication to thesecondary network node, wherein the full resume indication includes theresume identity.
 6. The method of claim 1, further comprising: aftersuspending the dual connectivity communication and before receiving themeasurement report, transmitting a partial resume indication to thewireless terminal, wherein the partial resume indication includes theresume identity; after sending the partial resume indication to thewireless terminal and before receiving the measurement report, resumingmaster cell group bearers, master cell group split bearers, andsecondary cell group split bearers for the dual connectivitycommunication with the wireless terminal while disabling secondarynetwork legs of the master and secondary cell group split bearers; afterreceiving the measurement report, transmitting a full resume indicationto the secondary network node, wherein the full resume indicationincludes the resume identity; and after transmitting the full resumeindication to the secondary network node, enabling the secondary networklegs of the master and secondary cell group bearers.
 7. The method ofclaim 1, wherein suspending the dual connectivity communicationcomprises suspending the dual connectivity communication to suspendbearers of both the main network node and the secondary network node. 8.A method of operating a network node supporting dual connectivity with awireless terminal as a secondary network node in cooperation with a mainnetwork node, the method comprising: providing dual connectivitycommunication with the wireless terminal in cooperation with the mainnetwork node; receiving a suspension indication message; responsive toreceiving the suspension indication message from the main network node,suspending the dual connectivity communication with the wirelessterminal; and while the dual connectivity communication is suspendedreceiving a measurement report from the wireless terminal via the mainnetwork node, the measurement report providing radio link informationfor radio links with the main network node and/or the secondary networknode.
 9. The method of claim 8, wherein the suspension indicationmessage includes a resume identity, the method further comprising:responsive to receiving the suspension indication message from the mainnetwork node, saving an access stratum, AS, context for the dualconnectivity communication with the wireless terminal so that the accessstratum context for the dual connectivity communication is maintained atthe secondary network node after suspending the dual connectivitycommunication with the wireless terminal, the access stratum context forthe dual connectivity communication including information regardingsecondary cell group, SCG, bearers for the secondary network node andbeing associated with the resume identity; after suspending the dualconnectivity communication, receiving a partial resume indication fromthe main network node, wherein the partial resume indication includesthe resume identity; responsive to receiving the partial resumeindication, resuming a secondary cell group split bearer for the dualconnectivity communication based on the access stratum context whiledisabling a secondary network node leg of the split bearer and whilemaintaining suspension of a secondary cell group bearer for the dualconnectivity communication; after resuming the secondary cell groupsplit bearer, receiving a full resume indication including the resumeidentity; and responsive to receiving the full resume indication,resuming the secondary cell group bearer for the dual connectivitycommunication based on the access stratum context and enabling thesecondary network node leg of the split bearer, wherein suspending thedual connectivity communication comprises suspending secondary cellgroup bearers and secondary cell group split bearers associated with thedual connectivity communication with the wireless terminal.
 10. Themethod of claim 8, wherein suspending the dual connectivitycommunication comprises suspending the dual connectivity communicationto suspend bearers of both the main network node and the secondarynetwork node.
 11. A method of operating a wireless terminal supportingdual connectivity with a main network node and a secondary network node,the method comprising: providing dual connectivity communication withthe main network node and the secondary network node; receiving aconnection release message from the main network node; responsive toreceiving the connection release message, suspending the dualconnectivity communication with the main network node and the secondarynetwork node; performing a radio link measurement with respect to themain network node and/or the secondary network node while the dualconnectivity communication with the main and secondary network nodes issuspended; while the dual connectivity communication is suspended,communicating with the main network node; and after communicating withthe main network node, transmitting a measurement report to the mainnetwork node, the measurement report including information based on theradio link measurement performed during suspension of the dualconnectivity communication.
 12. The method of claim 11, furthercomprising: responsive to receiving the connection release message,saving an access stratum, AS, context for the dual connectivitycommunication with the main and secondary network nodes so that theaccess stratum context for the dual connectivity communication ismaintained at the wireless terminal after suspending the dualconnectivity communication with the main and secondary network nodes,wherein the access stratum context includes radio resource controlconfigurations for the main and secondary network nodes, and whereinsuspending the dual connectivity communication comprises suspendingbearers of the main and secondary network nodes.
 13. The method of claim11, further comprising: before suspending the dual connectivitycommunication with the main and secondary network nodes, receiving ameasurement configuration message from the main network node definingradio link measurements to be performed by the wireless terminal whilethe dual connectivity communication with the wireless terminal issuspended, wherein performing the radio link measurement comprisesperforming the radio link measurement in accordance with the measurementconfiguration message.
 14. The method of claim 11, wherein communicatingwith the main network node comprises transmitting a resume request tothe main network node.
 15. The method of claim 11, wherein communicatingwith the main network node comprises receiving a page from the mainnetwork node indicating arrival of downlink data.
 16. The method ofclaim 11, wherein suspending the dual connectivity communicationcomprises suspending the dual connectivity communication to suspendbearers of both the main network node and the secondary network node.17. The method of claim 11, wherein the main network node and thesecondary network node are nodes of different radio access technologies,and wherein one of the main and secondary network nodes is an LTEnetwork node, and the other of the main and second network nodes is anNR network node.
 18. A network node configured to support dualconnectivity communication with a wireless terminal as a main networknode in cooperation with a secondary network node, the main network nodecomprising: processing circuitry; and memory coupled to the processingcircuitry and having instructions stored therein that are executable bythe processing circuitry to cause the network node to perform operationscomprising: providing dual connectivity communication with the wirelessterminal in cooperation with the secondary network node; responsive todeciding to suspend the dual connectivity communication with thewireless terminal, transmitting a connection release message to thewireless terminal; responsive to deciding to suspend the dualconnectivity communication with the wireless terminal, transmitting asuspension indication message to the secondary network node; responsiveto deciding to suspend the dual connectivity communication with thewireless terminal, suspending the dual connectivity communication withthe wireless terminal; while the dual connectivity communication issuspended, transmitting a page to the wireless terminal indicatingarrival of downlink data for the wireless terminal; and aftertransmitting the page during suspension of the dual connectivitycommunication, receiving a measurement report from the wireless terminalproviding radio link measurement information for radio links with themain network node and/or the secondary network node.
 19. A network nodeconfigure to support dual connectivity communication with a wirelessterminal as a secondary network node in cooperation with a main networknode, the secondary network node comprising: a transceiver configured toprovide wireless network communication with the wireless terminal; anetwork interface configured to provide network communication with themain network node; and a processor coupled with the transceiver and thenetwork interface, wherein the processor is configured to providecommunication with the wireless terminal through the transceiver,wherein the processor is configured to provide communication with themain network node through the network interface, and wherein theprocessor is configured to: provide dual connectivity communication withthe wireless terminal in cooperation with the main network node, receivea suspension indication message, and suspend the dual connectivitycommunication with the wireless terminal in response to receiving thesuspension indication message from the main network node; and while thedual connectivity communication is suspended receiving a measurementreport from the wireless terminal via the main network node, themeasurement report providing radio link information for radio links withthe main network node and/or the secondary network node.
 20. A wirelessterminal comprising: processing circuitry; and memory coupled to theprocessing circuitry and having instructions stored therein that areexecutable by the processing circuitry to cause the wireless terminal toperform operations comprising: providing dual connectivity communicationwith the main network node and the secondary network node; receiving aconnection release message from the main network node; responsive toreceiving the connection release message, suspending the dualconnectivity communication with the main network node and the secondarynetwork node; performing a radio link measurement with respect to themain network node and/or the secondary network node while the dualconnectivity communication with the main and secondary network nodes issuspended; while the dual connectivity communication is suspended,communicating with the main network node; and after communicating withthe main network node, transmitting a measurement report to the mainnetwork node, the measurement report including information based on theradio link measurement performed during suspension of the dualconnectivity communication.